Low-Level Jets and Their Effects on the South American Summer Climate as Simulated by the NCEP Eta Model*
Low-Level Jets and Their Effects on the South American Summer Climate as Simulated by the NCEP Eta Model*
复制标题
NCEP Eta 模型模拟的低空急流及其对南美夏季气候的影响*
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
M. Fennessy
中科院分区：
文献类型：
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作者：
A. Vernekar;B. Kirtman;M. Fennessy
利用美国国家环境预报中心(NCEP)再分析的侧边界条件，用80公里、38L的Eta模式模拟了1983、1985、1987、1989和1991年南美热带夏季(1-3月)的气候。对对流层低层环流和降水的模拟进行了分析，以研究日、季内和年际时间尺度上的变化。研究结果与观察结果和之前的研究结果进行了比较。与再分析相比，Eta模式产生了更好的区域环流细节，如低层急流(LLJ)，因为它具有更高的分辨率、更逼真的地形和海岸几何形状，以及它能够真实地模拟中尺度环流对时间平均气流的影响。该模式不仅能探测到安第斯山脉以东的LLJ和西部科迪勒拉北部以西的LLJ，而且它还能探测到在西科迪拉山以西的LLJ。
Abstract The National Centers for Environmental Prediction (NCEP) Eta Model (80 km, 38L) is used to simulate the tropical South American summer (January–March) climate for 1983, 1985, 1987, 1989, and 1991 using lateral boundary conditions from the NCEP–National Center for Atmospheric Research (NCAR) reanalysis. Simulations of the lower tropospheric circulation and precipitation are analyzed to study the variability on diurnal, intraseasonal, and interannual timescales. The results are compared with observations and previous studies. The Eta Model produces better regional circulation details, such as low-level jets (LLJs), than does the reanalysis because of its higher resolution, more realistic topography and coastal geometry, and because of its ability to realistically simulate the effects of mesoscale circulation on the time-mean flow. The model detects not only the LLJ east of the Andes Mountains and the LLJ west of northern Cordillera Occidental, which have been reported in previous studies, but it al...